1. Technical Field
This invention relates generally to a battery charger for simultaneously charging multiple batteries, and more particularly to a method and apparatus for simultaneously charging multiple batteries loaded in multiple charging pockets of a charger via current delegation between the multiple pockets.
2. Background Art
Portable computers, personal digital assistants, cellular telephones, pagers, calculators, and other such electronic devices are commonplace in today's mobile society. One of the reasons portable electronic devices are so popular is that they provide a user with virtual freedom regarding the location of their use, as long as a source of power is readily available. Although these devices may be powered by plugging them into a standard AC outlet, AC power is often not convenient or readily available. Hence, their real portability and utility comes from rechargeable batteries.
Although battery technology has progressed greatly in recent decades, a single battery is sometimes unable to meet a user's demand. For example, many cellular telephone service providers are offering plans with 3000 plus minutes of talk time or more per month. Some business people talk on their cellular phones six or more hours per day. Typical cellular telephone batteries provide only three to four hours of talk time before needing to be recharged. Consequently, some users carry two or more batteries with them so that a spare is ready when the first battery dies. Further, to remain on the go, users now want shorter charge times in addition to extended battery life. They also want to be able to quickly charge two or more batteries at the same time.
One solution to the problem of how to quickly recharge two or more batteries is to charge two batteries serially. In other words, when the two batteries are placed in the same charger, the charger completely charges the first battery. The charger then instantly switches to the second battery and charges it. Total charging time is thus the charging time of one cell multiplied by the number of cells. Another solution to the problem with quickly recharging multiple batteries was to charge each battery in a charging system with its own power supply or charging system.
However, both solutions present problems. A problem with the first solution is that it is not efficient. The second solution requires a prohibitive amount of manufacturing costs, components and space. For these reasons, there is a need for an adaptive, multiple battery charging apparatus that allows simultaneous charging of multiple batteries with a single battery charging system